Slipped

The book slipped from his lap and onto the floor.

The spy slipped the secret code into the message, without anyone realizing it.

The secret plan was slipped into a confidential memo, without anyone noticing.

She slipped and made an error in her calculations, resulting in an incorrect answer.

The package slipped from the delivery driver's hands and tumbled down the steps.

The key slipped out of the lock and onto the ground.

I slipped up and forgot to send the important email.

The spy slipped past the guard and entered the building undetected.